n-Butyl[4-[2-[2-hydroxy-5-(N-hydroxycarbamimidoyl)benzenesulfontylamino]ethyl]-2′-methanesulfonylbiphenyl-3-yl oxy]acetate hydrochloride represented by formula (I):
is a novel compound which has been found by the present applicant. This compound exhibits excellent inhibitory activities against activated blood coagulation factor X, and is useful for the treatment or prevention of a thromboembolic disease. Crystalline polymorphism of this compound has not been found so far.